Annoyed by constant flat battery for my power tools , few years ago I did convert some to use external power bank.
Lithium battery from my electric bike 24v 10Ah require me now to recharge only few times a year.
Some of my drills come with 2 NiCd batterries and already dead- so I removed battery and soldier an 2m extension cable with cigarette lighter plug.
Cigarette lighter socket is attached to battery.
Small inbuilt electronic controller allow to set-up any voltage from 0 to 24V
Now I can work as long as I want without worrying about flat battery. Drill is even lighter to handle without battery, just need to carry this battery bank near to the work place.
I suppose the future for all battery tools is now additional plug and cable the could connect any tool to small battery bank. Tool is still portable and never will run out of juice.